A critical skill for modeling geometries “beyond the wizards” is being able to change surfaces from interior to exterior and vice versa. Follow through this quick visual guide and you'll be able to handle a variety of obstacles the wizards can't handle well:

Here is a wall I am gong to change to an interior adiabatic surface. Note that clicking on the 3D view causes the tree view on the left to navigate straight to the surface in question.

Right-click any item under the space to create a new interior wall.

Choose to copy an existing interior wall - which one isn't critical.

Copy geometry information from the target to the exterior surface. TIP: If you select the same reference polygon, some of these fields will automatically populate with the values we're looking for. In general, the 3D view in the background will change dynamically as you alter surface geometries, so use it as a visual check if you're unsure about the surface azimuth and such.

Almost done! Notice the new wall is now white (adiabatic surface color)

Delete the exterior wall and it's child window, when prompted…

The finished product:

Armed with this knowledge, you can now tackle:

Creating models of single rooms or building portions with limited exterior faces

Modifying roofs/floors between stacked shells to correctly model staggered roofs and the like

Tying together spaces between shells that the wizards have trouble associating, for whatever reason.